Image projection apparatus, its control method, and storage medium

Patent metadata

Field	Value
Publication number	US-10948809-B2
Application number	US-201816229221-A
Country	US
Kind code	B2
Filing date	Dec 21, 2018
Priority date	Dec 27, 2017
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

An image projection apparatus includes an optical element configured to change a light amount of light emitted from the light source, an information acquirer configured to acquire information on a gradation of the image signal, a corrector configured to correct the image signal in accordance with a change in the light amount, and a controller configured to correct the image signal based on at least one of first correction data used to correct the image signal in accordance with the change in the light amount caused by controlling the optical element, and second correction data used to correct the image signal in accordance with the change in the light amount caused by controlling the supply power.

First claim

What is claimed is:

1. An image projection apparatus comprising:
an optical modulator configured to modulate light from a light source according to an image signal, the image projection apparatus being capable of projecting light modulated by the optical modulator to display an image;
an optical element configured to change a light amount emitted from the light source; and
a processor configured to:
acquire information on a gradation of the image signal;
correct the image signal; and
control the light source and the optical element based on the information on the gradation;
wherein the processor corrects the image signal based on first correction data used to correct the image signal in accordance with a change in a light amount caused by controlling the optical element and second correction data used to correct the image signal in accordance with a change in a light amount caused by controlling the light source.

2. The image projection apparatus according to claim 1 , wherein the processor is further configured to acquire a user set value relating to a brightness of the image,
wherein the processor sets a target value relating to a light amount according to the user set value and information on the gradation, and changes a light amount emitted from the light source by controlling the light source and a light amount emitted from the light source by controlling the optical element based on the target value.

3. The image projection apparatus according to claim 2 , wherein the processor changes the light amount emitted from the light source by controlling the light source and the light amount emitted from the light source by controlling the optical element between when the target value is larger than a predetermined value and when the target value is smaller than the predetermined value.

4. The image projection apparatus according to claim 1 , wherein the first correction data is correction data for correcting a color change in the image caused by controlling the optical element and the second correction data is correction data for correcting a color change of the image caused by controlling the light source.

5. The image projection apparatus according to claim 1 , wherein the processor is further configured to detect a degradation of the light source,
wherein the processor controls at least one of the optical element and the light source so as to suppress a decrease in the light amount entering the optical modulator due to the degradation when the degradation is detected.

6. The image projection apparatus according to claim 5 , further comprising a light amount detector configured to detect the light amount of the light source,
wherein the processor detects the degradation when detecting that the light amount has decreased with a predetermined supply of power to the light source.

7. The image projection apparatus according to claim 1 , further comprising a temperature sensor configured to detect an internal temperature of the image projection apparatus,
wherein the processor controls at least one of the optical element and the light source so as to decrease the internal temperature when the internal temperature is higher than a predetermined temperature.

8. The image projection apparatus according to claim 1 , wherein the information on the gradation is any one of an averaged gradation level, a gradation histogram, and a maximum gradation value.

9. A control method of an image projection apparatus that includes an optical modulator configured to modulate light from a light source according to an image signal, the image projection apparatus being capable of projecting light modulated by the optical modulator to display an image, the control method comprising:
changing a light amount emitted from the light source through an optical element;
acquiring information on a gradation of the image signal;
correcting the image signal; and
controlling the light source and the optical element based on the information of the gradation;
wherein the correcting the image signal corrects the image signal based on first correction data used to correct the image signal in accordance with a change in a light amount caused by controlling the optical element and second correction data used to correct the image signal in accordance with a change in a light amount caused by controlling the light source.

10. A non-transitory computer-readable storage medium for storing a computer program that enables a computer to execute a control method of an image projection apparatus that includes an optical modulator configured to modulate light from a light source according to an image signal, the image projection apparatus being capable of projecting light modulated by the optical modulator to display an image,
wherein the control method includes:
changing a light amount emitted from the light source through an optical element;
acquiring information on a gradation of the image signal;
correcting the image signal; and
controlling the light source and the optical element based on the information of the gradation;
wherein the correcting the image signal corrects the image signal based on first correction data used to correct the image signal in accordance with a change in a light amount caused by controlling the optical element and second correction data used to correct the image signal in accordance with a change in a light amount caused by controlling the light source.

Assignees

• Canon Kk

Inventors

• Kimoto Tatsuya
• Takanashi Ikuo

Classifications

• G03B21/2053 Primary

  Intensity control of illuminating light (controlled by video signal processing H04N5/74 or H04N9/31) · CPC title

• H04N9/3155

  for controlling the light source (light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406) · CPC title

• G03B9/00

  Exposure-making shutters; Diaphragms · CPC title

• H04N9/3194

  including sensor feedback · CPC title

• G03B21/147 Primary

  Optical correction of image distortions, e.g. keystone · CPC title